This member of the
Campanulaceae family was described by Mats Thulin in 1980. It is only
found in the cliffs of Mauritius, where it is disappearing from,
because of imported insects. It grows in small pockets of peat on
the step cliffs with some water and some sun. It raises for 40
centimetres, the flowers are pale blue, and besides seeds, it might
be possible to reproduce it from cuttings.

The plants are dusted
by birds, and it secretes scarlet-red nectar. Only two other plants
does that: Trochetia blackburniana and Trochetia
boutoniana, both also from Mauritius.

A team of Danish
researchers led by Jens Olesen (Aarhus University) has been studying
these Mauritian flowers to determine why red nectar evolved. They
point out that, since red nectar is extremely rare, it is unlikely
to provide any pollinating advantage, otherwise it would occur more
commonly. Does the red substance act as a signal or warning? During
observations, the researchers witnessed birds stealing nectar and
tearing flowers to pieces and concluded that 'seeing red' doesn't
deter nectar thieves or protect flowers.

Olesen and colleagues
instead suggest that red nectar may have coevolved with a
pollinating bird species that is now extinct. Since the 16th
century, the island of Mauritius has been steadily losing native
species due to habitat destruction and over-hunting. By 1680, 28
bird species had disappeared. Today there are just 11 native bird
species, eight of which are endangered. Perhaps the riddle of red
nectar may be answered by a ghost from the past. In the hope of
pinning down this ghost, the researchers are currently searching
among recently extinct Mauritian birds for likely candidates.